This invention relates to safety shackles and snap clips having attached safety lines, life lines or the like which may be used for various purposes, including the attachment of life lines to yachts, the attachment of life rafts/boats to ships in danger of sinking, the attachment of safety lines in rock climbing and the attachment of loads to cranes and other lifting devices.
Shackles for connecting life lines to the strong point on a yacht and/or for connecting the life line to the safety harness of the crew member commonly incorporate a quick-release mechanism in the form of a release catch having an axis of operation in the direction perpendicular to the direction of load on the shackle. This arrangement is most undesirable since the load applied to the shackle, being in a direction perpendicular to the direction of actuation of the release catch, often causes the release catch to jam thereby preventing release in what may be a life or death situation. Another disadvantage with the known release catch arrangement as used in snap clips and some snap shackles is that the catch is usually located externally of the shackle and in certain circumstances the catch may be accidentally released by the life line or other external means, such as a projecting part of the yacht, once again with the possibility of disastrous consequences.
In addition to the above, since the release mechanism for the latch is located near the strongpoint, it may be impossible for the crew member restrained by the life line to reach the release mechanism and then succeed in taking the load off the life line in order to undo the mechanism or snap clip, especially where the yacht sinks suddenly. A disadvantage of simply relying on a release clip at the wearer's end of the life line is that this system only encourages detaching of the life line when the wearer wishes to move around the boat. This is of course a most undesirable situation.
Although shackles having release actions which are substantially parallel to the direction of the applied load and shackles having remotely actuatable release mechanisms may be found in the literature, see for example U.K. Pat. No. 825575 Kjolner, French Patent Publication No. 2483791 Kaminski and U.S. Pat. Nos. 3493260 Smith and 4093293 Huggett, none of the described shackles has found commercial application for the uses outlined in greater detail above. The present inventors believe this may be due to the fact that the release line for each shackle is separate from the life line assembly and therefore creates the possibility of entanglement and inadvertent release. Furthermore, the remote release shackles described in the literature referred to above suffer from the disadvantage that they either require the shackle to be in a no-load condition for release or they require the release line to be in a taut condition. The latter problem is particularly evident where the shackle is to be released when the release line is in a tangled condition which often occurs with life lines for yacht crew members. Still further, all of the remote release mechanisms are of necessity actuated along a line which is spaced from the line of applied force and this may lead to jamming of the release line and may prevent the use of swivel joints where appropriate.